I agree that your bp is perfect! As for your higher than normal heart rate, perhaps they are giving you too much synthroid? Sometimes it takes a while to find the right dosage - too much and you are wired, too little and you are tired all of the time. My mom had the same surgery back in the 70s and had too little synthroid for a long time. Anytime she'd sit down for more than a few minutes she'd fall asleep. She finally found a good endocrinologist who worked with her to find the appropriate dosage.
Hope that helps, get well soon!
My thoughts are that the high pulse rate is anxiety following surgery. Also, your body is working harder to repair damaged tissue due to surgery.
As far as the blood pressure goes, 110/70 is an optimal reading, not low at all.
Best of luck!